[PATCH 4.4 1/1] can: dev: make can_change_state() robust to be called with cf == NULL

[Alexander Grund <theflamefire89@gmail.com>]

From: Marc Kleine-Budde <mkl@pengutronix.de>

In OOM situations where no skb can be allocated, can_change_state() may
be called with cf == NULL. As this function updates the state and error
statistics it's not an option to skip the call to can_change_state() in
OOM situations.

This patch makes can_change_state() robust, so that it can be called
with cf == NULL.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 2835aeb11c9f..eeeba3f5c8b4 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -341,6 +341,9 @@ void can_change_state(struct net_device *dev, struct can_frame *cf,
 	can_update_state_error_stats(dev, new_state);
 	priv->state = new_state;
 
+	if (!cf)
+		return;
+
 	if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
 		cf->can_id |= CAN_ERR_BUSOFF;
 		return;
-- 
2.40.1